Film and sheet capable of forming retortable and easy-open packagings

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Applicants have found that a wrappable film may be made which is capable of forming peel seals and comprises a mixture containing from about 5 percent by weight to about 25 percent by weight of an ethylenic homopolymer or copolymer, from about 50 percent by weight to about 70 percent by weight of a butene-1 homopolymer or copolymer, and from about 25 percent by weight to about 45 percent by weight propylene homopolymer or copolymer.
More preferably, the film composition comprises a mixture which contains from about 10 percent by weight to about 20 percent by weight of the ethylenic homopolymer or copolymer, from about 55 percent by weight to about 60 percent by weight of the butene-1 homopolymer or copolymer, and from about 25 percent by weight to about 45 percent by weight of the propylene homopolymer or copolymer.
Most preferably, the film composition comprises a mixture which contains about 10 percent by weight of the ethylenic homopolymer or copolymer, about 65 percent by weight of the butene-1 homopolymer or copolymer, and about 25 percent by weight of the propylene homopolymer or copolymer.
The ethylenic homopolymer or copolymer may be linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), ethylene vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA) ethylene-ethyl acrylate copolymer (EEA), ethylene-butyl acrylate copolymer (EBA), or high density polyethylene (HDPE) and is most preferably low density polyethylene or ethylene vinyl acetate copolymer.
The propylene homopolymer or copolymer is blended for improvement of the processability of the mixture and retortability (resistance to the temperature of the retort).
The novel polymer mixtures may be formed into an oriented or unoriented film by casting or film blowing method.
After fabrication the film can be heat sealed by sealing jaws at a preset temperature, pressure and dwell.
The seal strength is tested by an Instron tensile tester at 10"/min